Specific heat behavior of high temperature superconductors in the pseudogap regime

TL;DR

This paper investigates the unusual specific heat behavior in underdoped high-temperature superconductors, attributing anomalies to the pseudogap phase and order parameter fluctuations, supported by analytical and numerical models.

Contribution

It introduces a phenomenological model linking the pseudogap to specific heat anomalies, explaining experimental observations with modified electronic contributions and fluctuation effects.

Findings

Reduced specific heat jump explained by pseudogap effects

Normal state hump attributed to order parameter fluctuations

Model aligns with experimental data on cuprates

Abstract

Experimental data obtained from thermodynamic measurements in underdoped high temperature superconductors show unusual anomalies in the temperature dependence of the electronic specific heat both in the normal state and at the critical point associated to the superconducting phase transition. The observed deviations from the standard behavior are probably linked with the opening of a pseudogap in the energy spectrum of the single-particle excitations associated with the normal state. Based on a phenomenological description of the pseudogap phase we perform analytical and numerical calculations for the temperature dependence of the specific heat for both the superconducting and normal state. The reduced specific heat jump at the transition point can be explained by a modified electronic single particle contribution to the specific heat in the presence of the normal state pseudogap. The hump observed in the normal state specific heat can be explained by the electronic pair contribution associated with strong fluctuations of the order parameter in the critical region. The obtained theoretical results are discussed in connection with experimental data for cuprates.